This one starts off like a classic monster movie. Avaricious humans disturb ancient and powerful creature. Creature proceeds to pick off humans, one by one.
In this case, the humans are miners seeking something called Pergium, and the creature is a pile of rocks with a penchant for disintegrating people with a powerful acid. The Enterprise is called in to help.
This episode, which ran near the end of the first season, includes some great exchanges between Kirk, Spock, and McCoy, including one of McCoy's greatest lines: "I'm a doctor, not a bricklayer."
William Shatner has said that "The Devil in the Dark" is his favorite Star Trek episode.
